Patent term calculation is complicated in the US because there are essentially two different systems and quite a few corner cases. Even with a list of patents, it can be tricky to determine when the patents are all expired. Since I am a computer programmer (and not a lawyer), I created a program to try and automate this. This paper discusses how patent term calculation works, and some results from a combination of hand and automatic term calculation for MP3, MPEG-2 and H.264.

I am not really that concerned since we have Vorbis, Speex, Theora, VP8 and others which come very close and in many cases surpass the patented offerings. These are examples of the very best in engineering efforts, as evading patented technologies and still making a superior product is so complicated.

Aside from Vorbis, Speex, Theora and VP8 the "others" which you mention that may be useful are Dirac, FLAC and CELT.

FLAC is lossless, which is useful where storage space or bandwidth is not the prime concern, but quality is. Digital mastering is an application that comes to mind. The newest audio codec from Xiph.org is CELT, which is useful for Speech, VoIP, Low latency, Studio/transmitter link, wireless audio. Exactly the opposite scenario, where bandwidth and low latency are the primary considerations.

As far as I know, Vorbis, FLAC and CELT are actually the best codecs to use in each of the scenarios they are designed for. Vorbis is better than mp3, for example, FLAC is as good as any other lossless format, and CELT is as good as any other for low latency, low bandwidth application.

There has been a lot of argument over the comparitive performance of VP8 versus H.264, but when it first was released by Google out VP8 was very marginally behind the best H.264 encoder. VP8 however has twice been upgraded by Google since then, with approximately 6% performance improvements each time, and the third upgrade codenamed "Cayuga" is due out very soon now.